In recent years control systems have been used to alleviate the task of operators of agricultural vehicle systems. Automation allows an operator to concentrate on other tasks such as coordinating transport. Moreover, such control systems guarantee constant performance throughout the day whereas an operator gets tired.
Control systems on agricultural vehicle systems can only take into account information collected by the agricultural vehicle system at a time t in the past. However, an experienced operator looks ahead and estimates from a previous pass what the machine behavior at a next location might be. A good control system should also anticipate on e.g. the crop condition, just like an experienced operator would. The operator may make a visual assessment of the condition in terms of, for example and amongst others, crop density in front of the machine and/or farmland slope, and acts upon it.
At present, automatic control systems do not have this upfront information, which makes it hard to have an automated system that is as efficient as an experienced operator. A lot of research has been performed into sensors to measure the harvest condition in front of the machine.
U.S. Pat. No. 5,995,895 describes a control system in which a predetermined geo-referencing map is stored in a memory circuit, the geo-referencing map including site-specific spatially-variable map data indicative of anticipated conditions along the course of travel which may affect the engine load. The control system calculates the anticipated condition using at least actual location signals and the stored map data, and generates a control signal based at least upon the anticipated condition. It is a disadvantage of this system that the geo-referencing data has to be available, either from a previous pass with the same vehicle over the field (geo-referencing data stored when vehicle passed over the field during a previous season for example), or from a pass with another vehicle over the same field (in which case the geo-referencing data needs to be transferred from one vehicle to another).
DE19528663 describes a method for controlling an agricultural vehicle system, which is provided with at least one measurement device for determining its position, and at least one further measurement device for determining a control value for controlling the operation of the agricultural vehicle system. The method controls the action of the vehicle system itself, e.g. its speed, by taking into account at least one predicted process variable and/or area feature, wherein during the calculation of the at least one predicted value, use is made of at least one previously recorded measurement at a particular location. For the prediction of the process variable and/or area feature at a location X, all measurement values of this process variable and/or area feature already obtained before within a range with predetermined radius around location X are taken into account. Different possibilities are set out. In one embodiment, the predicted value may be a mean value of the already measured values within the range. In another embodiment, a weighted value of already measured values within the range may be built whereby different weights are assigned to different measured values depending on their distance from location X within the pre-determined range, taking into account the direction of the change of the measurement values. In yet another embodiment, the prediction may be done solely on the basis of a measurement value of a location adjacent the location of which the prediction is to be made. It is a disadvantage of the model used in DE19528663 that predictions are not accurate enough.
There is room for improved control systems for agricultural vehicle systems.